It seems that the binary format output by jgltf-browser 2.0 is incorrect

I tried saving glTF file in binary format using jgltf-browser 2.0. The following is the procedure I tried.

1. [Samples] - [Khronos Sample, v2.0] - [Duck] - [glTF (https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0/Duck/glTF/Duck.gltf)]
2. [File] - [Save as binary…] - [Duck.glb]
3. [File] - [Open file…] - [Duck.glb]

The following error is displayed.

Loading error: java.io.IOException: Could not load glTF asset
java.util.concurrent.ExecutionException: java.io.IOException: Could not load glTF asset
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
	at javax.swing.SwingWorker.get(SwingWorker.java:602)
	at de.javagl.swing.tasks.SwingTask.get(SwingTask.java:435)
	at de.javagl.jgltf.browser.GltfLoadingWorker.done(GltfLoadingWorker.java:170)
	at de.javagl.swing.tasks.SwingTask.callDone(SwingTask.java:473)
	at de.javagl.swing.tasks.SwingTask.access$200(SwingTask.java:74)
	at de.javagl.swing.tasks.SwingTask$SwingTaskWorker.done(SwingTask.java:108)
	at javax.swing.SwingWorker$5.run(SwingWorker.java:737)
	at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.run(SwingWorker.java:832)
	at sun.swing.AccumulativeRunnable.run(AccumulativeRunnable.java:112)
	at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.actionPerformed(SwingWorker.java:842)
	at javax.swing.Timer.fireActionPerformed(Timer.java:313)
	at javax.swing.Timer$DoPostEvent.run(Timer.java:245)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:109)
	at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:184)
	at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:229)
	at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:227)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:227)
	at java.awt.Dialog.show(Dialog.java:1084)
	at java.awt.Component.show(Component.java:1671)
	at java.awt.Component.setVisible(Component.java:1623)
	at java.awt.Window.setVisible(Window.java:1014)
	at java.awt.Dialog.setVisible(Dialog.java:1005)
	at de.javagl.swing.tasks.DefaultSwingTaskView.show(DefaultSwingTaskView.java:70)
	at de.javagl.swing.tasks.SwingTaskExecutor.doExecute(SwingTaskExecutor.java:360)
	at de.javagl.swing.tasks.SwingTaskExecutor.execute(SwingTaskExecutor.java:318)
	at de.javagl.jgltf.browser.GltfLoadingWorker.load(GltfLoadingWorker.java:125)
	at de.javagl.jgltf.browser.GltfBrowserApplication.openUriInBackground(GltfBrowserApplication.java:559)
	at de.javagl.jgltf.browser.GltfBrowserApplication.openFile(GltfBrowserApplication.java:500)
	at de.javagl.jgltf.browser.GltfBrowserApplication.access$000(GltfBrowserApplication.java:76)
	at de.javagl.jgltf.browser.GltfBrowserApplication$1.actionPerformed(GltfBrowserApplication.java:106)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
	at javax.swing.AbstractButton.doClick(AbstractButton.java:376)
	at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)
	at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)
	at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
	at java.awt.Component.processMouseEvent(Component.java:6533)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
	at java.awt.Component.processEvent(Component.java:6298)
	at java.awt.Container.processEvent(Container.java:2236)
	at java.awt.Component.dispatchEventImpl(Component.java:4889)
	at java.awt.Container.dispatchEventImpl(Container.java:2294)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
	at java.awt.Container.dispatchEventImpl(Container.java:2280)
	at java.awt.Window.dispatchEventImpl(Window.java:2746)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.awt.EventQueue$4.run(EventQueue.java:729)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: java.io.IOException: Could not load glTF asset
	at de.javagl.jgltf.browser.GltfAssetReaderThreaded.readGltfAsset(GltfAssetReaderThreaded.java:288)
	at de.javagl.jgltf.browser.GltfLoadingWorker.doInBackground(GltfLoadingWorker.java:162)
	at de.javagl.jgltf.browser.GltfLoadingWorker.doInBackground(GltfLoadingWorker.java:59)
	at de.javagl.swing.tasks.SwingTask.doTaskInBackground(SwingTask.java:335)
	at de.javagl.swing.tasks.SwingTask.access$000(SwingTask.java:74)
	at de.javagl.swing.tasks.SwingTask$SwingTaskWorker.doInBackground(SwingTask.java:84)
	at javax.swing.SwingWorker$1.call(SwingWorker.java:295)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at javax.swing.SwingWorker.run(SwingWorker.java:334)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

[javagl]

The bug was fixed in https://github.com/javagl/JglTF/commit/a7f214b11347371c79088572ecd9c31bad523e8a

The main problem (besides the copy+paste error) was that the chunkLength was set to be the length of the whole chunk (inculding the chunkLength and chunkType slots), but this is wrong. While the length field in the header refers to the whole file, the chunkLength is not the length of the whole chunk, but only the length of the chunk data.

(Actually, the IO is already tested with a unit test, but the GLB that the test output was compared against was already wrong - this is also fixed now)

Thanks again for bringing this up.

[javagl]

I think that it is almost correctly displayed in JglTF, but since it is dark overall, it feels good to set the lights a bit more bright. (or it would be nice to be able to set the light settings as options.)

Setting the light options would certainly be a second step. As you know, most viewers allow selecting an environment light map. One problem is: Purely metallic objects look pretty cool with environment maps, but with “simple” lights, they appear all black. (E.g. the floor of the polly model)

I hope that I can integrate (selectable) environment maps in JglTF, too. And of course, the other lights should not just be one single point light, but all sorts of lights that will soon be required for the KHR_Lights extension anyhow.

Although this should be interesting, it is not the top priority right now.